EDM constraint on NP associated with BEH bosonFanrong Xu (徐繁荣 )

National Taiwan University

Nov. 8, 2013 @ AS

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Introduction0

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Introduction

“Discovery” of Higgs Boson rated year’s top scientific achievement of 2012.

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The life of Higgs

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Production

Decay

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The discovery @ LHC Signal Strength

ICHEP2012, summer 2012

HCP2012, winter 2012

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Higgs XSWG

Once upon a time, there was a hot word called

“h-gamma-gamma”…

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The discovery @ LHC

Moriond 2013

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EW

QCD

excess or fluctuation?

What could be hidden

in current data: NP or SM?

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The discovery @ LHC

EPS-HEP 2013

LS1

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Further Identification Spin and CP

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J. Bendavid, EPS-HEP 2013

excludes hypothesis at

no significant discrimination yet

D. Schaefer, EPS-HEP 2013

More data is required for accurate analysis of spin and CP!

What information of spin and CP can be digged out from current data?

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NP

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Byproduct: Cutoff Scale Mass scale of exotic degrees of freedom: (0.4~8) TeV

(cutoff)

CMS@ICHEP2012

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ATLAS@HCP2012

Can we get a hint for the NP scale?

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Strategy

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SM+NP

EDM+(g-2)

EFT

Based on We-Fu Chang, Wei-Ping Pan and FX, PRD 88,033004 (2013).

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Gauge-Higgs Operators1

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Effective Theory

Bottom-up approach: SM is the low energy effective theory; The full Lagrangian can be expanded by (1/cutoff)

There are limited (59) gauge invariant independent dimension-6 operators

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GIMR, JHEP10 (2010)085;BW, NPB268 (1986) 621.

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Effective Theory

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Effective Operators Motivated by diphoton excess and DOF(s) beyond SM, we assume New Physics can be captured by the effective gauge-Higgs operators

These operators form a subset, the other 3 gauge-Higgs operators are strictly constrained by EW precision tests.

The RG running effect will not be involved in this work.

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Manohar, Wise;X. Zhang, B.-L. Young;McKenn,Pospelov,Ritz

……

GJMT, 1301.2588; MEMP,1302.5661

Oblique correction: S

QCD theta term

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Effective interactions

CP even/odd tree level h-V-V’ interaction is brought in

Also anomalous gauge coupling is introduced

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SM-like Anomalous coupling

CP-even CP-odd

Effective coupling : the combination of WCs

Form factors

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Higgs Physics2

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Production and decay

Signal strength: co-determined by both production and decay

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Error source: PDF +

Higgs XSWG

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Modification @ loop level

diphoton decay:

production: gluon fusion dominates

unmeasured decay channel:

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CP-even CP-odd

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Modification @ tree level The tree level decay SM contribution is contained in CP-even part, phase space integral of 3-body decay needs to be treated.

Assumptions

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All the final state fermions are summed up

All the fermions are massless

CP-even CP-oddGHO @ AS,2013/11/08

Numerical Analysis

Numerical expressions at cutoff 1TeV

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Rescaling:

The story of 6 parameters

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Pseudo global fit

Input experimental data (up to Moriond 2013)

68 % C.L. correlation among alpha’s:

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Current LHC data agrees with SM;Larger GF production smaller Higgs decay width

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Constraint on Wilson coefficients

95 % C.L. correlation among Wilson coefficients:

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Both CP-even and CP-odd Wilson coefficients have a boundary CP-even Wilson coefficients are well constrained, a few Constraints on CP-odd sector are poor, There is still allowance for NP, from SM theoretical errors.

SM:

LHC:

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Constraint on Effective couplings

The constraints on Wilson coefficients can be translated to constraints on effective coupling

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The effective coupling can be obtained after a coordinate rotation from WCs.

This coupling strength is checkable by different groups.

SM

LHC

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The relation between ZZ and WW:

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The boundary of decay width ratio and signal is obvious

A linear relation of signal strength between WW and ZZ is found

SM

LHC

Prediction

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EDM, MDM3

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EDM

EDM and MDM have different CP property

nEDM in SM

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EDM Current nEDM

Current eEDM

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UK US

ACME collaboration, 1310.7534

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AMDM

AMDM: the SM deviation from experimental measurement provides a room for NP SM calculation:

Measurement: muon: muon (g-2) col.,

2006

electron: Hanneke et. al., PRA2011

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GHO @ Nankai U.,2013/09/22

Aoyama-Hayakawa-Kinoshita., 2007

Less known

2-loop

HVP LBL

3

1.3 but error could be reduced

EDM and AMDM in EFT

One loop EDM and g-2 can be generated due to the effective operators

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CP-odd (EDM); CP-even (g-2)

McKeen-Pospelov-Ritz, PRD86, 113004 (2012)

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Constraint on CP-odd sector Neutron and electron EDM upper bound provides a constraint

on 3D space.

Project to 2D plane by setting the third parameter in a certain region,

But the combination of EDM and Higgs can largely reduce allowed region

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EDM constrain parameter on a long and narrow band

Higgs best fit

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Constraint on CP-even sector

With a best fit of muon and electron g-2, a linear relation is obtained

g-2, giving another band with different slope from Higgs constraint, helps to further determine parameter space of CP-even sector.

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g-2 Higgs best fit

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A global constraint on WCs Take into account all the above experiments, we can get a

limited region in Wilson coefficient space.

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CP-odd sector are severely constrained, reduced to order of 1, which also gives an indication for NP models.

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Constraints on effective coupling

The constraints on Wilson coefficients can be translated to constraints on effective coupling

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SM

LHC

The stringent constraint on the CP-odd sector, O(100)O(1), is because of EDM.

g-2 does not improve the constraint on CP-even sector too much.

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The relation between ZZ and WW:

The interesting relation between WW/ZZ and AZ

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But hard to detect

Prediction

SM

LHC

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Discussion4

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1. Discriminate c3

In the presence of effective operators, we have

One way to discriminate the degenerate solutions is by Higgs pair production in future LHC experiments.

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The solution will bring a large deviation from SM, and would be easily checked (ruled out) by future experiments.

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2. Wise-Manohar Model

Wise-Manohar model: color-octet scalar

Custodial symmetry leads to and

The physical CPV phase appears in potential, could it be the source of CP-odd operators?

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WM, PRD’06; HVY,JHEP’11

……

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The mechanism to generate effective operators

From a naïve dimensional analysis, constraints on model parameters can be obtained from current LHC data

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CP-even CP-odd

CP-even operators can be generated at 1-loop level;

CP-odd operators cannot be generated purely from potential.

2. Wise-Manohar Model

a complement to WM modelGHO @ AS,2013/11/08

The mechanism to generate effective operators

Such a toy model

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CP-even CP-odd

CP-even operators can be generated at 1-loop level;

CP-odd operators can be produced by adding CP-violating Yukawa interaction.

2’. Another UV-complete model

Chang, Pan and Xu, work in progressGHO @ AS,2013/11/08

3. Prediction for CPV decays

CP violation fraction

A not very predictive prediction (hard to analyze CP for photon)

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The CPV fraction in WW/ZZ mode is small

There could be large CPV component in gamma-gamma/gamma-Z mode

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Summary5

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We have provided an EFT approach to 125 GeV Higgs boson, and find even all Higgs decay channels agree with SM predictions, SM theoretical uncertainty still provides a room for NP.

From current LHC data we have got a global constraint of Wilson coefficients, which indicates NP models, a toy model is constructed as a typical example.

From current LHC data, we find a linear relation between WW and ZZ, and get the limits of signal strength for different di-boson decay modes.

When EDM and AMDM are taken into account, CP-odd operators are constrained severely. An interesting relation between ZZ(WW) and gammaZ is predicted.

The potentially interesting CPV fraction in diphoton and gammaZ mode is pointed out.

We also provide a way to discriminate a degenerated solution of c3.

Summary

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Backup: Another toy model

Color 27-plet scalar + two vector-like fermion

Scalar potential is same as color octet model The typical diagrams for generating CP-odd gauge-Higgs

operators

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